Well, there are a few different ROMS that boast about their extra speed.
Among the ones I'm familiar with would be No2Chem's, DCD's, and the Titan Kitchens built with PPCKitchen, particularly the latest 20270 build.
At present I'm running the latter, the 20270 build and I'm getting 23 MB of RAM free after a soft reset.
I love how smooth this build is. It seems to fly comparitve to the other ROMS I've loaded up, but so have the No2Chem ROMS I've loaded.
As you may know from your Q, it's alot of trial and error to find the ROM that suits you best.
Just flash a few and tinker with them for a while and see what you like.
